Review on 🔧 Lead-Free Soldering Flux Paste Jars - 2 Jars Solder Flux for Electronics DIY, Rosin Soldering Flux for Improved Soldering (1.2oz/35g Each) by Geoff Cooper

Although there are flux syringes, I like these because I feel like I have much more control over how much I use ( although you should never be afraid to use flux). Again, this one doesn't clean, so it won't corrode your connections if you have to leave it because you don't have solder mask yet. I just scraped off a little with a toothpick and either did my best to scrape it off the right spot or just melted it drop by drop with an iron. Worked pretty well!